Telegraph exchange for lines with simplex or duplex characteristics



June 3, 1952 R. M. M. OBERMAN 2,599,344

TELEGRAPH EXCHANGE FOR LINES WITH SIMPLEX OR DUPLEX CHARACTERISTICS Filed Oct. 1, 1947 2 sHEETs sHEET I;

FDLRRIZED lTL.Z R

POLARIZED ROELOF HHHRTEN MRAEVESEZZMBN June 3, 1952 R. M. M. OBERMAN 2,599,344

TELEGRAPH EXCHANGE FOR LINES WITH SIMPLEX OR DUPLEX CHARACTERISTICS Filed 001?. l, 1947 2 SHEETSSHEET 2 L L L L L L O o O O o O O o O O O O 6 1-K) 1L J-[m Q8 PIJLARIZED FROM FINAL SELECTOR POLARIZED INVENTOR ROELOF MHHRTEN nnm'a Patented June 3, 1952 UNITED STATES PTENT 2,599,344 F Fl CE Roelof M. Oberman, The Hague, Netherlands Application October 1, 1947, Serial No. 777,139 In the Netherlands July 2 6, 1941 "Section 1, Public Law 690, August 8, 1946 Patent expires July 26, 1961 10 Claims.

The present invention relates to telegraph systems, and more particularly, to telegraph systems comprising an exchange to which a plurality of subscribers in connected.

Heretofore systems have been described in which subscriber lines each terminate in a repeaterin the exchange so as to obtain a system in which a number of connecting lines may be interconnected in simple manner without danger of signal distortion or of a reduction of operating speed.

Also systems are known in which each subscriber line is terminated in the exchange by a repeate'r.

In U. S. Patent Specification 1,959,412 a bidirectional telegraph system worked on subscriber lines of identical nature has been described in which a repeater is added in the connecting circuit between lines.

The telegraph system according to the invention comprises a number of subscribers connected to the several exchanges by lines which may be simplex or duplex, these lines being provided as required in the exchange with a repeater the circuit of which adapts itself automatically to the number nature of the incoming or outgoing connecting lines in a manner not resulting in signal distortion or limitation in speed of operation.

Several advantages over the known telegraph systems are obtained by the present invention, such as the fact that the line of the subscriber does not terminate in the exchange in an in variable repeater but in a repeater circuit which adapts itself to the simplex and duplex lines so that a great economy is obtained.

The adaptation of the single current subscriber line to the repeater may be obtained by artificially prolonging these lines by means of suitable networks to a standard length. The circuit may also be arranged thus that the network required at the incoming end of the single current subscriber to provide for the adaptation of the repeaters common to the subscriber lines is maintained as an individual unit so that. a constant desired adaptation of the line tothe repeater is effected.

The repeaters in the system of the invention are so arranged that their circuit adapts itself automatically to the number nature of the incoming and of the outgoing lines, the adaptation of the repeater to the line being unvaryingly the same as required.

The incoming subscriber line may be suitable at the subscribers desire for simplex or duplex single current traffic double current lines being for instance provided for district subscribers, these being either fitted with fixed line terminations or not.

i The outgoing connections may be of the same nature as mentioned, such that incoming and outgoing connections of different nature may be interconnected as required. The repeater isfnot only suitable to the interconnection of subscriber tem exchanges or to other types of semi or fullautomatic exchanges.

The drawings show the system of the invention only in so far as it is necessary for a proper understanding of the same.

Fig. 1 shows the circuit of a local subscriber and the terminating circuit of a district subscriber.

Fig. 2 shows the main parts of the transmission circuit of a link.

In the upper part of Fig. 1 the circuit of a local subscriber set is shown which is provided with the arrangement according to the invention for working simplex and duplex. This subscriber is connected to the exchange by two pairs of wires. In the lower part of Fig. 1 the repeater is shown having a double current line, which may be the connection to the exchange of a district subscriber or of another exchange. Furthermore, an apparatus is shown individual to the subscribers, and serving to terminate the lines, which apparatus consists of the line and cutoff relays and, for the single current lines, of the compensating resistance adapting the telegraph relays in the adaptable repeater to these lines.

Fig. 2 shows the main parts of the connecting link with the adaptable repeater, in which polarized relays OVR and ZR are the local receiving and transmitting relays, respectively.

In connection with the repeater circuit a call finder OZ and the first selecting stage, group selector GK, are shown, while in the lower part of the figure the register is shown with its connections to a register finder RZ, only as far as is required for the explanation of the invention. The relays EDRI and EDR2 discriminates the incoming and outgoing junction lines, respectively, in single current and double current lines and adapt the corresponding parts of the repeater to the kind of current used on these lines.

Operation of relays DR! and DB2 adapts the repeater to duplex-single current traific; such operation may be efiected at will by the subscribers. The functions of the other relays will be clear from the following description. 4

The adaptation of the repeater, which in normal condition is switched for double current lines, to a calling single current subscriber will now be described. In normal condition of the subscribers set in Fig. l, a circuit is closed from -battery, over the winding of line relay LRI, the back contact of the upper change-over contact of the cut-off relay CORI, resistance R8, back contact of the upper change-over contact of relay HR, the winding of polar relay ER, the

back contact of the lower change-over contact of relay COR! to ground. In this condition, owing to the resistance R8, the current in the circuit amounts to about 5 ma., the line relay LRI being safely kept at normal by a current of 5 ma.

Furthermore the current direction is such, that the polarized relay ER keeps its contact opened as shown, so that the printer motor M is stopped. On pressing the calling key OT resistance R8 is bridged by relay AR. The current in the subscribers loop now increases so much, that the operation of the relays LRI in the exchange and AR in the subscriber's set is accomplished. Relay AR bridges with its front contact the calling key OT, which then has only momentarily to be operated.

At the operation of the line relay LRI, in consequence of an incoming call, the call finders, allotted to the call are started. In Fig. 2 a free call finder OZ with a repeater is shown; the local subscriber is connected to the first contacts in the rows of contacts of the call finders. The upper front contact of line relay LRI applies negative test voltage over a resistance R4 to the first contact of contact row e in all the call finders of this group.

At the receipt of a starting mark in one of the line relays, common starting relay ASR is operated in a circuit from battery, its own winding, the lower front contact of relay LRI to ground. j

The front contact of relay ASR closes in its turn operating circuits for the starting relays SRI of allappropriate call finders. The driving magnets of the call finders are now energized, the front contacts of relays SR! close circuits similar to that shown in the drawing from bat tery, the winding of driving magnet KM, a make contact of starting relay SR], cut-off contacts of test relay CR and cord seizure relay KBR to ground. Call finder OZ and the other free call finders are permitted to start.

If call finder OZ of Fig. 2 is the first to reach the calling subscriber line, the test relay CR is energized in a circuit from battery, resistance R4, a make contact of relay LRi in Fig. 1, wiper e of call finder OZ and the high resistance winding of relay CR to ground. At the operation of relay CR, make contact applies ground to the low resistance Winding of relay CR, whereby the current increases so much, that the negative test voltage at the contacts in the e-rows of all call finders becomes insufiicient for the operation of other test relays CR. In this manner double tests in this stage of building up the connection are prevented.

In a way analogous to the seizure of a free call finder, a number of register finders are started, one of which connects the calling subscriber to a free register. On the operation of test relay CR ground is applied to a common register startingrelay RSR, which closes with'i'ts front contact circuits for the starting relays SR2 of a number of appropriate register finders.

Fig. 2 shows a free register finder RZ. Relay SR2 applies ground to the driving magnet KMI of the register finder over the right hand bank contact of relay RBR, the left hand back contact of relay RCR and its own make contact. If the register finder RZ arrives first of all at the contacts of the calling connecting link, test voltage is applied to the high resistance winding of relay RCR by means of the contact in the row a of the register finder. On the operation of relay RCR the register finder stops and the low resistance winding of relay RCR is connected to ground, in order to prevent double tests.

As the register test relay RCR is energized at the moment when a free register is found, operating circuits are closed for two holding relays, namely for the register holding relay RBR, which remains operated during the holding time of the register in a circuit from battery, the'winding of relay RCBR and a right hand make contact of relay RCR to ground, and for the cord holding relay KBR a circuit from battery, the winding of relay KBR, the b-wiper of the register finder RZ, a make contact of relay RCR and the make side of the change-over contact of relay RBR to ground. Relay KBR which has a controlling function in the connecting circuit and in the register, holds itself after the connections to the register are switched off, in a circuit over its own make contacts and the make contacts of the slow releasing guarding relays CRI and CR2,

these relays being operated in a manner, which will be described hereinafter.

The operating of the cord seizure relay KBR has some consequence, which have an extraordinary significance in the system according to the invention. First relay ,CORI operates in a circuit from battery, the winding of relay CORI, the c-wiper of the call finder OZ and the make side of the change-over contact of relay KBR to ground, whereby the relays LRI, CR and RCR are released. Negative test voltage is no longer applied to the contacts of the e-row of call finder OZ so that effective protection against double tests is provided.

Furthermore circuits for the relays, discriminating the kind of calling line, are closed in a manner now to be described. The d contacts in the call finder OZ, belonging to incoming single current subscriber lines, are connected to ground over an individual compensating resistance R3, shown in Fig. 1. In contro-distinction thereto, the decontacts belonging to incoming double current lines, are not connected.

If the d-wiper encounters ground, in case a single current subscriber is calling, relay EDRI operates in a circuit from battery, winding of relay EDRI, the back side of its make-beforebreak contact, a make contact of relay KBR,

call finder wiper d and the local compensating resistance R3 to ground. Thereafter relay EDRI holds itself over the make side of its own makebefore-break contact and a make contact of relay .KBR. As the magnetisation of relay EDRI is.v

the line, over the a-wiper of a callfinder OZ, and to.

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th dup eh the transm t in l1 tre n itting .oontacts E and the xethe e i n m ehe eye s1 ehe eer-reeheh he heirs h Wi e reee he ihe-iht ee eeee v he :r lee OVR end the hee. f the i ee l te hem hfe T e. i-eeh m t-ine eetelhehe heye am le e heh e-eeh ee he the up ex e he tiehis W tee v le ,hhi hee 1B1!!- Th eehsex her et/1 hhee-ee; ehnh ex lin condition. When relay D133 is in norm a l poitieh eh is, eehhee d in ehee plex v in ee 5 h e r h .i 4 er Q hxee ie w h h ine 1 11 +i e eeee h Windin PR1 he eeh v R! end -w eer e QZ 'e eeem k eehteet 9 rel-es 1 3 eehe mele e eeii lewer eheheei i gimme la QOBL :tel rep ey- 1d bymeen e the me ee elde of it 7 el; een eeteh i qihee gi i ex so ween +hett r h 2he eeiet re th hhe Q0111 he ed 9 the lb w eer e the eellaflheer OZ- V a repea er circ i i es-t b shed in w i h he-extremit s e th windin s e re ay 9 3 re ehheete l the ewe me her es eieeleeeeier impleX-eqndition- HQWBYQI, the iunctienei the d n s se n ectedte e e r -ph bat r ver a. make contact of relay DR}.

B -pueh ne hey BT12 th subsc ber ma a a mter-mpt the epeitetihe ei eh t e r a D33, wherebmhis relay and rel y QB! in the eehne t 12% ine ere r eased en h e hhee e .e reee et rtWhrd th caller beeeme e ein s mplexi e eel ne ubee"' e. n eenh e 1 3B .eh rete i elese e uit h'fie. elite he xeee-r y heee e 01in thereeis er.

Aft he :reeerehn eithe umherh -th V .i we a e t :eheth .ezeehehee e he em the xch n e Q te ed; Yd e hemmt envthe hemmed umbe if ine-is found freeeele t e Whieh mey'ibeelene a m'kipe e the ne st e e e it from eentee end the driv n M eehet Q1 he roupree eet i en r Ever ste mad h t e er u z eleeter ite in e id nt, manner :in a -energi e n ef the xe ey U in the ee st r the n mber o te s b ing e h e led b the re -isterwh n IOHP= l Q QI he m -e number o -.sv.t.ep. h e eer e ends t9 umb :re e ded the r gi e eehie al i eeen d :e d r le fim heeu i ihemeem v -the ereel subs e i re th ee ne ende 9.1T ela OR! will be in home-1 mm .l i o eeeteeiheeir MH-rem tee-y, the :dhle e the Q DDQd l1 1ay@QRL ehn et h W re rte thee te ehdiheeentaet in the e of h fi e -se e t r h e wipers ef the ouple t rs, th wind n of :relay KIR n t e n et -ne nk and e m h n eeLQi re ay KBR zer uhd- Re y .K' T i thus peerated after which the relays EDR-ZQQQDR2 eglapt the eree eh ine; e d .of :the

fi eelee e fe owin t t ere he elee 2 e ei-reh -t is e; ehe.d t e reley'n i z ever 1 eelectq f i W nted-b the te t e by theih e; 0h i the ehr e in the ber-lee! e 'reeel .e thee ere Q eer spondi ley COR!) exeeieter eet h may then he e m nated. by th. w-i hihe h h relay KER h Wh eh t thi em t hee-hee li Wen e t n e th reei e er pe e of th eie e fi de Ro fhreinee eis the t ns o th i d ng o one eeeil :ree ving rel We en o o a h smi heee Y Z -threueh-e hn eteel net the t ngue Qf'hh he er e p x the o ue eiriheee e e se e eeohhee e t the ee e -v -he e ile e he ehhse e? From this omen the eeeh ifiee ie e mh eh h l e subs r er mey be tran m t ed, s t at h u eihe m now trgnsmit hi -name and number toward the caller e signal, that the connection is establiehed.

During the several actions describegl, circuits a e e tabl shed fe t w u er is ry rele e R! d CR By the a i o r la EBB- the ieheheh h ehe ndi gs .ef the Jeee heley Q i ee hee ed rte +h ttex -rin h e eet-er e er e me ee eehteet e rel y E 1 e cut-eff e h eei e? q ele QR 2 3 e= th t he M. o M dime -t0 e ee er eelee eeh hee ery it t it he a rea y eeei this "side- Re y GR! is now=.ene i d eltaphhaittery siet h e e11 I e i meg,-

ing to an open make contact of relay EDRI.

7 spacing side of the local receiving relay OVR tongue to +telegraph battery. Relay CR2 operates likewise in a circuit from -telegraph battery, make contact of relay KBR, CR2 windings, cut-off contact of relay KDR, g-wiper of register finder RZ to +battery in the register.

The function of the relays CR1 and CR2 is to establish a holding circuit for the cord seizure relay KBR, which circuit may be interrupted by thes relays when desired by the subscribers. Relay CRI supervises the connection toward the calling subscriber, relay CR2 supervises the connection toward the called subscriber. The caller, as well as the called subscriber, are able to interrupt the connection by pushing the release key ST of Fig. 1 for some moments, e. g. 200 milliseconds. This key interrupts, when pushed down by the calling subscriber, the loop terminated by the local receiving relay OVR, and when pushed down by the called subscriber, the loop terminated by the local transmitting relay ZR. As a consequence the tongues our or 21', respectively, of the relays OVR or ZR, move over to battery for a time which is long enough to release the slowly actuated relay CRI or CR2. The breaking of the holding circuit of relay KBR restores the link to free condition. Relays CR! and CR2 must be slow releasing relays, since they are not to release, when during the spacing elements of the repeated telegraph signals the tongues of the relays O=VR and ZR are brought against battery.

If the connection is not yet fully completed, the caller may stop the building up of the connection by pushing the release key ST, causing relay CRI to be released, whereas the register may release the connection by demagnetizing relay CR2, if the called subscriber is found busy. The word busy may be transmitted to the caller by the register, before the release occurs. From the foregoing description of that adaptation of the repeater to a single current line and the building up of the connection between subscribers, it will be clear that the repeater is in normal position suitable for the interconnection of double current lines, as relays EDRI, EDRZ, DR! and DR2 are in non-operated position.

As described hereinbefore the contacts in the d-row of the call finders OZ are not connected to ground for double current-lines. Thus after the operation of the cord seizure relay KBR. no ground is applied to the relay EDRI, this relay remaining now operated. As the operating circuit for relay DR! contains a make contact of relay EDRI, relay DRI does not operate either. The windings of the local receiving relay OVR are switched in series between the tongue of the trunk receiving relay ITL.OVR and ground, over a cut-on" contact of relay EDRE. The junction of the windings remains unconnected, ow-

The trunk transmitting relay ITLZr is over the b-wiper and cut-01f contacts of relays EDRI and DRI, connected to the tongue of relay ZR, when junction lines of which to the exchange -are In normal condition the; armature of the trunk -receivingrelay I'ILQVR double" current lines.

is against pole of battery. At an incoming" subscribers call, which is characterized in the emission of +vo1tage on the trunk line by the subscriber, the tongue is moved toward +pole' of battery, and line relay DR? is energized in a circuit from +te1egraph battery, over the tongue of relay I'IL.O-VR, the back contact of the upper change-over contact of relay CORZ, and the windings of relay LRZ to battery; The consecutive switchings, resulting in the seizure of a" free connecting link and a free register, follow in" the same manner as described for a single cur-' rent subscriber.

As soon as the relay KBR operates, ground is applied to the left hand winding of relay OVR, and the tongue of this relay moves over to the +side of telegraph battery, as marking current Thus the operis sent by the calling subscriber. ating circuits for slow releasing supervising relays" CRI and CR2 are established.

It is observed, that subscribers connected to the exchange over double current lines have also possibility to work duplex with the arrangement of the invention. These subscribers are connected over a local single current line to a repeater, inverting the single current signals to double current signals over the interlocal double current line to the exchange. The trunk junction lines are suitable for duplex-traflic. The adaptation of the subscriber set to the four wire traffic, which has only consequences on the single current part of this connection to the exchange, has no influence on the condition of the trunk junction line and the repeater in the connecting link of the automatic exchange. I

While I have illustrated and described what I regard to be the preferred embodiment of my invention, nevertheless it will be understood that such is merely exemplary and that numerous modifications and. rearrangements may be made therein without departing from the essence of the invention, I claim:

1. Telegraph system comprising in combination, an exchange; a plurality of subscribers; single current lines and double current lines for connecting each of said subscribers to said exchange; means operated by said subscribers, respectively, for changing said single current lines from two-wire (simplex) lines to four-wire (duplex) lines and vice versa; a repeater circuit in said exchange; and means in said repeater circuit for discriminating between simplex and duplex among said single current lines.

2. Telegraph system comprising in combination, an exchange; a plurality of subscribers;'

single current lines and double current lines for connecting each of said subscribers to said exchange; means operated by said subscribers, respectively, for changing said single current lines from two-wire (simplex) lines to four-wire (duplex) lines and vice versa; a repeater circuit in said exchange; a relay in said repeater circuit for discriminating between single and doublechange, said exchange including apparatus in-L dividual to one of said subscribers and serving to terminate said subscribers line; neutral relays forming part of and constituting said apparatus i;

means operated by said subscribers, respectively, for changing said single current lines from twowire (simplex) lines to four-wire (duplex) lines and vice versa; a repeater circuit in said exchange; and means in said repeater circuit; for discriminating between simplex and duplex among said single current lines.

4. Telegraph system comprising in combination, an exchange; a plurality of subscribers; single current lines and double current lines for connecting each of said subscribers to said exchange, said exchange including apparatus individual to one of said subscribers and serving to terminate said subscribers line; neutral relays forming part of and constituting said apparatus; means operated by said subscribers, respectively, for changing said single current lines from twowire (simplex) lines to four-wire (duplex) lines and vice versa; a repeater in said exchange; a combination of relays in said repeater circuit for discriminating between single and double current lines among said lines; and a combination of relays in said repeater circuit for discriminating between simplex and duplex lines among said single current lines. a

5. Telegraph system comprising in combination, an exchange; a plurality of subscribers; single current lines and double current lines for connecting each of said subscribers to said exchange, said exchange including apparatus individual to one of said subscribers and serving to terminate said subscribers line; neutral relays forming part of and constituting said apparatus; means including switches and relays operated by said subscribers, respectively, for changing said single current lines from two-wire (simplex) lines to four-wire (duplex) lines and vice versa; a repeater in said exchange; and a relay in said repeater circuit for discriminating between single and double current lines among said lines.

6. Telegraph system comprising in combination, an exchange; a plurality of subscribers; single current lines and double current lines for connecting each of said subscribers to said exchange, said exchange including apparatus individual to one of said subscribers and serving to terminate said subscribers line; neutral relays forming part of and constituting said apparatus; means including switches and relays operated by said subscribers, respectively, for changing said single current lines from two-wire (simplex) lines to four-wire (duplex) lines and vice versa; a re peater in said exchange; a relay in said repeater circuit for discriminating between single and double current lines among said lines; and a relay in said repeater circuit for discriminating between simplex and duplex lines among said single current lines.

7. Telegraph system comprising in combination, an exchange; a plurality of subscribers; single current lines and double current lines for connecting each of said subscribers to said exchange, said exchange including apparatus individual to one of said subscribers and serving to terminate said subscribers line; neutral relays forming part of and constituting said apparatus; means including switches and relays operated by said subscribers, respectively, for changing said single current lines from two-Wire (simplex) lines to four-wire (duplex) lines and vice versa; a re peater in said exchange; a combination of relays in said repeater circuit for discriminating between single and double current lines among said lines; and a combination of relays in said repeater circuit for-discriminating between simplex and duplex lines among said single current lines.

8. Telegraph system comprising in combination, an exchange; a plurality of subscribers; single current lines and double current lines for connecting each of said subscribers to said exchange; resistances associated, respectively, with said single current lines and limiting the current thereof to a constant output; means operated by said subscribers, respectively, for changing said single current lines from two-wire (simplex) lines to four-wire (duplex) lines and vice versa; a repeater circuit in said exchange; a relay in said repeater circuit for discriminating between single and double current lines among said lines; and a relay in said repeater circuit for discriminating between simplex and duplex among said single current lines.

9. Telegraph system comprising in combination, an exchange; a plurality of subscribers; single current lines and double current lines for connecting each of said subscribers to said exchange, said exchange including apparatus individual to to one of said subscribers and serving to terminate said subscribers line; resistances associated, respectively, with said single current lines and limiting the current thereof to a constant output; neutral relays forming part of and constituting said apparatus; means operated by said subscribers, respectively, for changing said single current lines from two-wire (simplex) lines to four-wire (duplex) lines and vice versa; a repeater in said exchange; a combination of relays in said repeater circuit for discriminating be tween single and double current lines among said lines; and a combination of relays in said repeater circuit for discriminating between simplex and duplex lines among said single current lines.

19. Telegraph system, comprising in combination, an exchange; a plurality of subscribers; single current lines and double current lines for connecting each of said subscribers to said ex-. change, said exchange including apparatus individual to one of said subscribers and serving to terminate said subscribers line; resistances associated, respectively, with said single current lines and limiting the current thereof to a constant output; neutral relays forming part of and constituting said apparatus; means including switches and relays operated by said subscribers, respectively, for changing said single current lines from two-wire (simplex) lines to four-wire (duplex) lines and vice versa; a repeater in said exchange; a relay in said repeater circuit for discriminating between single and double current lines among said lines; and a relay in said repeater circuit for discriminating between simplex and duplex lines among said single current lines.

ROELOF M. M. OBERMAN/ nnransncas orrnn The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,800,019 Hewett Apr. 7, 1931 2,114,324 Weld Apr. 19, 1938 2,176,963 Hallden Oct. 24, 1939 2,199,284 Duerr Apr. 30, 1940 2,228,890 Singer Jan. 14, 1941 FOREIGN PATENTS Number Country Date 531,902 Great Britain Jan. 14, 194i 

